Abstract: In order to prevent the spontaneous combustion of residual coal oxidation heat accumulation in goaf from inducing mine fires, this article takes the goaf of 40201 working face of Xiaozhuang Coal Mine as the research object, the O₂ and CO concentration in goaf were measured on-site, Matlab was used to obtain the distribution law and contour map of O₂ and CO concentration, the O₂ concentration was used as the dividing index of spontaneous combustion "three zones", and the distribution range of spontaneous combustion "three zones" in goaf of the test working face was obtained. The O₂ and CO concentration was superimposed to determine the range of high risk area in goaf, and the maximum production shutdown and rectification time of the working face was calculated to be 7 d. The distribution of spontaneous combustion "three zones" in goaf can be shown in a real and intuitive way, which can provide technical support for the implementation of fire prevention and suppression work in goaf of Xiaozhuang Coal Mine, and ensure the safety coal winning of 40201 working face.